1, a seven-digit number has seven digits, and from the highest bit to the lowest bit, it is 100,000, 1 00, 10 and 1 0 respectively. The value range of each number is from 0 to 9. Because we want to find the largest seven digits, we hope to get the largest number in each digit, which is 9. So the biggest seven digits should be 9999999.
2. The minimum value of seven digits, and the value range of each digit is from 0 to 9. However, in this problem, we need to find the smallest seven digits. In order to make the minimum number as small as possible, we take 0 as the value of most significant bit. So the smallest seven digits should be 1000000.
The Concept of Mathematical Numbers and Related Knowledge
1. Mathematical digit is a mathematical concept, which is used to represent the composition of a number in a certain system. For any number, it can be expressed as the product of several different decimal powers, where each power can be expressed as an integer and a positive integer.
2. The mathematical digits of a number are the digits contained in its representation in a certain system. For example, the decimal number 100 1 has four digits because it contains four digits.
3. For any number, if it is expressed as the product of several powers of different systems, then each power can be expressed as an integer and a positive integer. For example, the decimal number 23 can be expressed as 2 1 * 3 0, where both 2 and 3 are single digits; The decimal number 25 can be expressed as 5 2, where 5 is a single digit.
4. In numerical comparison, if the mathematical digits of two numbers are different, the size can be judged directly according to their mathematical digits. For example, in decimal system, the number of mathematical digits of 25 is 3, and the number of mathematical digits of 3 is 1, so 25 is greater than 3.
5. Mathematical numbers are also related to other mathematical concepts. For example, in computer science, binary, octal, decimal and hexadecimal can be converted to each other, and the conversion of decimal requires the concept of mathematical numbers. In addition, in mathematical analysis, the concept of real number also needs the concept of mathematical digits.